1. Field of the Invention
The present invention relates to switching assemblies, and more specifically, to switching assemblies, and/or optical switches used for testing optical fibers, devices, and/or fiber optic devices, such as fiber optic couplers. The present completely, accurately, and reliably tests a fiber optic device for some, many and/or all relevant optical characteristics.
2. Background of the Related Art
Fiber optic devices are typically tested after manufacture to determine their optical characteristics. For example, attenuators may be tested to determine the actual attenuation of the device, and fiber optic couplers may be tested to determine the coupling ratio at selected wavelengths and polarizations.
Currently, various techniques and/or switching assemblies are available for testing of fiber optic devices. For example, FIGS. 1A-1B illustrate one testing assembly disclosed in United Kingdom Patent Application 2235043A to Philip C. Longhurst, incorporated herein by reference. In FIG. 1A, an optical measurement system measures insertion loss of each fibre in sequence of a multi-fibre connector 15 connected to an optical fibre ribbon 16 to be obtained using light source 17, 18 and detector 22 of the system. A multi-channel optical switch 1 is connected to a light source 17, 18. A 1.times.2 bi-directional splitter 2 is optically coupled between each of the switch channels 4 and a respective fibre 8 of a standard multi-fibre connector 3 mating with the connector 15 to be tested. Optical fiber 5 is fusion spliced at 6 to the channel 4 and to one of the fibers 8 of an optical fiber ribbon 7 connected to the connector 3 by an optical fiber 9 which is fusion spliced at 10.
FIG. 1B is an illustration when the optical measurement system is used to monitor and record the return loss between the pair of optical fibers interconnected by the mating of the standard multi-fibre connector 3 and the multi-fibre connector 15 under test. To perform the return loss test, the adaptor 21 and large area detector 22 (shown in FIG. 1A) are disconnected and removed from the end of the optical fibre ribbon 16. The free end of the optical fibre ribbon 16 is immersed in an index matching gel 23 from which no light will be reflected. The testing for the return loss is then conducted using light source 17, 18 and additional detectors 19, 20.
Thus, in the Longhurst reference, the testing procedure is complex and cumbersome. Further, all desired properties of the fiber optic device cannot be tested without additional connections being made, and/or operations being conducted and/or additional testing equipment being required, between different test procedures. Thus, the testing system in the Longhurst reference is inefficient and not sufficiently and/or adequately automated.
FIG. 2 is an illustration of another prior art switching assembly; that is, the transmission measurement facility described in Bellcore Generic Requirements for Fiber Optic Branching Components, Bellcore GR-1209-CORE, Issue 1, November 1994, incorporated herein by reference. The source switch 112 is used to launch light from one of sources 104 selected via switch 106 into any of the devices under test 108 in environmental chamber 110. The detector switch 114 connects any DUT 108 to the power meter 118, measuring transmitted power and reflected power. The coupler 116 directs the optical power reflected by the DUT 108 to port (r) on Switch 114 for detection. A reference fiber 120, located at port (m) of Switches 112, 114 is used to correct for variations in source power over time. A reflectance reference 122 is located at port (r) of Switch 112, and is used to calculate reflectance from the measured optical power.
Insertion loss is calculated by subtracting the power transmitted through the reference fiber 120 from the power transmitted through the DUT 108. Reflectance is calculated by subtracting the power reflected by the reflectance reference 122 from the power reflected by the DUT 108. The Switches, Power Meter and Environmental Chambers are computer controlled via GPIB interface. However, I have realized that this switching assembly (suggested for use for environmental testing of fiber optic devices) cannot be used to collect and/or capture sufficient data to define a full transfer matrix needed to calculate/determine the prescribed device characteristics for adequate and/or sufficient fiber optic device testing. For example, this switching assembly cannot obtain or collect directivity and/or near end crosstalk measurements of a fiber optic device.
It is therefore desirable to provide a testing assembly capable of completely, accurately, and reliably testing a fiber optic device for some, most, and/or all relevant optical characteristics.
It is also desirable to provide a testing assembly capable of completely, accurately, and reliably testing a fiber optic device, such as an optical fiber biconical taper (FBT) coupler.
It is also desirable to provide a testing assembly capable of completely, accurately, rapidly, and reliably testing a fiber optic device without altering or changing the test configuration and/or testing equipment.
It is also desirable to provide a testing assembly capable of completely, accurately, rapidly, and reliably testing a fiber optic device without requiring the connections between the testing device and the device under test (DUT) to be altered or changed during the testing operation.
It is also desirable to provide a testing assembly capable of completely, accurately, rapidly, and reliably testing a fiber optic device without altering or changing the test configuration and/or testing equipment, while also connecting to, and/or disconnecting from, and/or simultaneously testing, another device under test.